Consolidated Statements of Changes in Stockholders’ Equity (Unaudited) (USD $) In Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member] Outstanding Common Shares Repurchased [Member]	Treasury Stock [Member] Shares Repurchased To Fund Options Exercised [Member]	Treasury Stock [Member] Shares Repurchased To Satisfy Tax Obligations [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance, beginning of period at Dec. 31, 2011	$ 315	$ 195,628				$ (7,355)	$ 223,510	$ 4,813
Repurchase of outstanding shares			(1,282)	(548)	(370)
Change in net unrealized gains (losses) on securities available for sale, net of taxes of approximately $2,013 and ($962) for the three months ended March 31, 2013 and 2012, respectively								1,217	1,217
Amortization of actuarial losses, net of taxes of approximately ($135) and ($117) for the three months ended March 31, 2013 and 2012, respectively								149	149
Amortization of prior service credits, net of taxes of approximately $5 for the three months ended March 31, 2013 and 2012)								(6)	(6)
Net income							7,129		7,129
Cash dividends declared and paid on common shares ($0.13 per common share for the three months ended March 31, 2013 and 2012)							(3,965)
Award of common shares released from Employee Benefit Trust (133,656 and 146,735 common shares for the three months ended March 31, 2013 and 2012, respectively)		1,363
Shares issued upon vesting of restricted stock unit awards		151				1,343	(97)
Issuance upon exercise of stock options		73				802	(24)		548
Stock-based compensation activity, net		4
Stock-based income tax benefit		106
Balance, end of period at Mar. 31, 2012	315	197,325			(7,410)		226,553	6,173	422,956
Balance, beginning of period at Dec. 31, 2012	315	198,314				(10,257)	241,856	12,137	442,365
Repurchase of outstanding shares			(301)	(637)	(653)
Change in net unrealized gains (losses) on securities available for sale, net of taxes of approximately $2,013 and ($962) for the three months ended March 31, 2013 and 2012, respectively								(2,594)	(4,203)
Amortization of actuarial losses, net of taxes of approximately ($135) and ($117) for the three months ended March 31, 2013 and 2012, respectively								174	174
Amortization of prior service credits, net of taxes of approximately $5 for the three months ended March 31, 2013 and 2012)								(6)	(6)
Reclassification adjustment for losses included in net income, net of taxes of approximatley $1,249 for the three months ended March 31, 2013								(1,609)	(1,609)
Net income							6,756		6,756
Cash dividends declared and paid on common shares ($0.13 per common share for the three months ended March 31, 2013 and 2012)							(3,973)
Award of common shares released from Employee Benefit Trust (133,656 and 146,735 common shares for the three months ended March 31, 2013 and 2012, respectively)		1,563
Shares issued upon vesting of restricted stock unit awards		78				1,983	(99)
Issuance upon exercise of stock options		55				691	(35)		637
Stock-based compensation activity, net		(120)
Stock-based income tax benefit		245
Balance, end of period at Mar. 31, 2013	$ 315	$ 200,135			$ (9,174)		$ 244,505	$ 8,102	$ 443,883